Add logout endpoint to Authentication Service

[dariogmori]

No description provided.

[jjgancfer]

A logout endpoint to the webapp should also be added.

[dariogmori]

For the logout endpoint the following approach was chosen in #87 :
When called the /logout method will delete the refresh token from the database, no longer allowing for its refresh until /login is called again. The JWT token though, will not be invalidated and shall expire naturally. Due to the short lifespan nature of the JWT tokens (1hour or so) this does not represent a significant security flaw and simplifies implementation.

[jjgancfer]

The API logout endpoint has already been merged into develop.

[dariogmori]

The login and logout should be fixed since they dont redirect to the proper things in the frontend.

[gony02]

Right now, the logout is working.